Problem with ActiveSync/TouchDown and From address

Hi,

ZCS 8. We have accounts with aliases and I want to send as the alias from my phone. It works fine with iOS but not with Android (using native or TD). No matter what I put in anywhere, it always uses my login name (ID@ad.blah.com) instead of my alias (name@blah.com). Setting Reply-To in Android or the mail preferences in the web UI don't help.

How can I set the default outgoing address to the alias, either globally or per-domain or per-user?